I run Windows 8 on my ThinkPad T530 (i7-3720QM + NVS 5400M). I want to completely disable adaptive contrast, but the best I could get is disabling it only when my laptop is plugged in. Moreover, if I plug in the power adapter while my system is suspended - it doesn't get detected by Intel drivers and I have to re-plug it in after the wake up. I tried all the relevant options for both AC and battery modes in Intel HD Graphics settings and Windows control panel as well, nothing helps. I didn't have this issue on Windows 7. All drivers are up-to-date.

I understand you want to disable the Adaptive Contrast for the Intel® HD Graphics 4000.

Please note that there is an option on the Intel® Graphics and Media Control Panel software to disable this feature.

You may follow the next steps to disable it from the software:

Open Intel® Graphics and Media Control Panel by right clicking in the desktop and selecting Graphics Properties

Once the software is open, you may click on Media > Image Enhancement > Adaptive Contrast Enhancement

Uncheck the Adaptive Contrast Enhancement option.

By following the steps mentioned above the feature will be disabled from the software.

However, please note that since you have an OEM system, it I also a good idea to contact the technical support from the system manufacturer to know if they may have included another software that allows the user to disable this feature.